Day 26: Statistics for Business Applications

• Last Time: Testing the difference in two proportions

• Collect homework 13.4

• Collect review exercises (optional) to replace a homework assignment.

• Questions about old stuff?

• Today:
  • Difference in proportions

    • Example: 3.111, p. 444

      Warning to confidence interval testers!

    • M & Ms
      • Does your proportion of browns differ from the 30% expected?
      • Is there evidence that you and your neighbor have different proportions of browns?

  • Introduction to linear regression: "...to predict the value of one variable on the basis of other variables."
    • Example: Heights of NKU students: males versus females.
      • To capture the "distance" (in minutes) for the one person who didn't give a time, I used linear regression on the data that four people provided.

    • Example: 18.8, p. 614

    • What's going on? How does linear regression work?
      • Do scatter plots indicate a linear relationship?
      • "Correlation" measures a linear relationship.
      • How do we find a "best-fit" line?
      • How good is that line?

• Next time: Regression (Section 18.1-3)

Links:

• A nice on-line course about regression